Eayre



E. O. BARTLETT. MANUFACTURE OF DRY WHITE LEAD.

1%. 100,353. Patented Mar.l,11870.

and soar fiatcnt @flilitr.

hettc'rs Patent No. 100,353, dated March 1,1870.

nunzovsrmrm m. can mamrmcrm or DRY wan-n LEAD.

The Schedule referred to in these Letters Patent and making part of the same.

To all whom it may concern:

Q Be it- Irnowu that I, EAYRE '0. BhRTLETT, of Birmingham, in Woorsmark township, Huntington coun-' ty, Pennsylvania, have invented a new and useful Im- [movement in the Manufacture of Dry White Lead and white-lead pigment from galeua, (native sulplrirret of lead and I do hereby declare that the tbllowing is a full and exact description of the sarrre.

, Heretofore dry white lead or the basis of white lead-pigment has been made from metalliclea d by the use ofac'id.

' When. galena (native-sulplnrret of lead) has been used it has been first reduced to metallic lead.

The process mostgencrally pursued. in making dry white lead, or the basis of white-lead pigment, from nretallic'lead, isby the use of acetic acid in earthen vessels immersed in decomposing matter, such as dung or tau.

This treatment i'cqtrilies from five to twelve weeks.

The leadis then ground, washed, and dried before it is fit tobc used-as a. basis ofa pigment.

I have discovered that by Lreating the ordinary gulcna, (native suiphuretof lead,) in an ore-crusher, and then roasting it; in an ordinary desulphurizing kiln or oven, and then mixing it with carbon, preferably in the state oftine-washed pen. or dust anthracite coal,

in'thc proportion of half and half, and then heating the mixture in aicornpound reducing aud'oxidizing furnace, dense white fumes or vapors pass oh". These are conveyed into a separate chamber or receptacle, where the vapors are strained by passing, through bags or screens of muslin, or other fabric, or are allowed to deposit by being passed slowly through an extended chamber in the way in which larnpblack, oxide ofzino, &c., have been heretofore collected.

To prevent the tiuxing of the mass together and otherwise to facilitate the subsequent operations, caustic lime or the carbonate of lime (in the form of pulverized limestone or otherwise) may be added to the mixture of carbon, and roasted ore in the proportion of about two hundred pounds of lime to every four hundred pounds of the galena. This addition is not essential, although under some circumstances it is desirable and beneficial.

llind; that lead inthis condition will form, when mixed with oil, a superior white pigment. It differs from and issnpcrior in quality as a pigment to the white oxide of zinc, or anything heretotbre producedti'o'm mixed metallic ores.

The product obtained-l1 my said process may be used not only as the basis of pigment, but as a drier,

and in all mamrfacturcs .wbere pure white oxide of lead is desired.

The furnace which I have found to work well for thepurposes above mentioned is commonly known as the \Yefhhrcll zinc furnace, for which Letters Patent of the United States were granted to Samuel Wethcrcll, November 13, 1855, No. 13,806., andwhich is represented in the annexed drawings, in whichn is the main chamber, the bottonrb' of which is composed of iron bars, perforated with small holes of The size of the holes would be such as to prevent the crushed ore and coal from falling through. These perforated bars are suitably sustained at the ends on the front and back walls 0 d.

The-ash-pit below the perforated bottom is of equal area therewith, and is provided with a door, 0, in front, and with a hole, f, at the back, for the reception of a pipe from suitable blowing apparatus.

The walls 9 g and arch or top It. should be built of some refractory substance, such as tire-brick.

The front is entirely open, and .providerl' with sliding doors 1', by which it can be closed when working the process or open to remove the residuum And at the back there are two sliding jambs j j, to give access to the main, charubcr for stir-tingthe charge and for inspection.

At the back near the arch there is a hole, 1:, governed by a sliding damper, leading to a chimney for carrying ofl' smoke and irupnre gases in the beginningof the operation on anew charge.

In the center of the roof there is an aperture, 1',

governed by a danrper'or sliding door, m, leading to a suitable apparatus for the collection of the oxidized vapors of lead. I

The exterior walls n 01) q may be built above the top to form two feeding troughs, r r, one on each side of the arch or roof, and provided each with an aperture or passage, 3, leading to the inside or main chamber, and each apertureor passage is provided with a cover to be put on after the furnace has been charged.

Having thus described my invention,

I claim, and desire to secure by Letters. Patent- 1. The rnanufrwture ofthe basis of a pigment, by treating galena (native sulphurot of lead,) by roasting and afterward mixing the roasted mass with carbon, and subjecting it to the action of heat in a compound reducing and oxidizing furnace, and collecting the fumes, as above described 2. The employment of lime in the form of caustic lime, orthe carbonate of lime, in combination with roasted galena and carbon in a compound reducing and oxidizing furnace, substantially as described. 4 3. Roasting galena, (native sulphuret of lead,) and then strbliming the sanre,and oxidizing the vapors, and collecting them as formed in a separate chamber, for the purpose of forming a basis of pigment and for other purposes, substantially as set forth.

4. As a new rnrurufacture, a white oxide of lead, produced by roasting the galena, then sublirning and oxidizing the same, and collecting it in a separate chamber.

EAYRE 0. BARTLETT.

Witnesses:

Gnorieu E. BUCKLEY, W- A. A. MoKmLnY. 

